Datasheet LT1070, LT1071 (Linear Technology)

LT1070/LT1071 5A and 2.5A High Efficiency Switching Regulators
U FEATURES DESCRIPTIO
■ Wide Input Voltage Range: 3V to 60V The LT®1070/LT1071 are monolithic high power switch- ■ Low Quiescent Current: 6mA ing regulators. They can be operated in all standard switch- ■ Internal 5A Switch (2.5A for LT1071) ing configurations including buck, boost, flyback, for- ■ Very Few External Parts Required ward, inverting and “Cuk”. A high current, high efficiency ■ Self Protected Against Overloads switch is included on the die along with all oscillator, ■ Operates in Nearly All Switching Topologies control and protection circuitry. Integration of all func- ■ Shutdown Mode Draws Only 50µA Supply Current tions allows the LT1070/LT1071 to be built in a standard ■ Flyback Regulated Mode Has Fully Floating Outputs 5-pin T0-220 power package. This makes it extremely ■ Comes in Standard 5-Pin TO-220 Package easy to use and provides “bust proof” operation similar to ■ Can be Externally Synchronized (Consult Factory) that obtained with 3-pin linear regulators.
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The LT1070/LT1071 operate with supply voltages from 3V
APPLICATIO S
to 60V, and draw only 6mA quiescent current. They can deliver load power up to 100W with no external power ■ Logic Supply 5V at 10A devices. By utilizing current mode switching techniques, ■ 5V Logic to ±15V Op Amp Supply they provide excellent AC and DC load and line regulation. ■ Off-Line Converter Up to 200W ■ The LT1070/LT1071 have many unique features not found Battery Upconverter ■ even on the vastly more difficult to use low power control Power Inverter (+ to –) or (– to +) ■ chips presently available. They use adaptive antisat switch Fully Floating Multiple Outputs drive to allow very wide ranging load currents with no loss ■ For Lower Current Applications, See the LT1072 in efficiency. An externally activated shutdown mode
USER NOTE:
reduces total supply current to 50µA typical for standby This data sheet is only intended to provide specifications, graphs and a general functional description of the LT1070/LT1071. Application circuits are included to show the capability of the operation. Totally isolated and regulated outputs can be LT1070/LT1071. A complete design manual (AN19) should be obtained to assist in developing new generated by using the optional “flyback regulation mode” designs. This manual contains a comprehensive discussion of both the LT1070 and the external components used with it, as well as complete formulas for calculating the values of these built into the LT1070/LT1071, without the need for components. The manual can also be used for the LT1071 by factoring in the lower switch current rating. A second Application Note, AN25, which details off-line applications is available. optocouplers or extra transformer windings. , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO Maximum Output Power* Boost Converter (5V to 12V)
100 L2 10µH 80 BOOST 5V L1** OUTPUT C3 BUCK/BOOST 150µH FILTER 100µF 60 VO = 30V D1 FLYBACK V 12V IN 40 V POWER (W)** SW 1A ISOLATED + R1 + C2 LT1070 10.7k C3* 1000µF 20 1% 100µF BUCK/BOOST FB GND V V C O = 5V 0 R2 R3 0 10 20 30 40 50 1.24k 1k INPUT VOLTAGE (V) 1% C1 1µF 1070/71 TA02 ROUGH GUIDE ONLY. BUCK MODE P * OUT = 5A • VOUT. *REQUIRED IF INPUT LEADS ≥ 2" SPECIAL TOPOLOGIES DELIVER MORE POWER 1070/71 TA01 **PULSE ENGINEERING 92113
DIVIDE VERTICAL POWER SCALE BY 2 FOR LT1071 **
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